CURSOR users_counters IS (
    SELECT
       COUNT(users.id) AS Number_of_Users,
       country.country_name AS Country
    FROM
        users,
        users_city,
        city,
        country
    WHERE
        users.id = users_city.users_id AND
        users_city.city_id = city.id AND
        city.country_id = country.id
    GROUP BY country.country_name
)

CREATE OR REPLACE FUNCTION convert_to_celsius
   ( temperature IN NUMBER )
   RETURN NUMBER
IS
   converted_temperature NUMBER;

BEGIN

    converted_temperature := (temperature - 32) / 1.8;

RETURN converted_temperature;

CREATE OR REPLACE FUNCTION convert_to_fahrenheit
   ( temperature IN NUMBER )
   RETURN NUMBER
IS
   converted_temperature NUMBER;

BEGIN

    converted_temperature := temperature * 1.8 + 32;

RETURN converted_temperature;